In most applications it is advantageous to hermetically seal many or all of the electronic die and other optical components that combine to form an OSA (optical subassembly) or other assembled or partially assembled optical communications module. Conventional hermetic sealing of electronic die and other optoelectronic components requires extensive mechanical design and considerable tooling and materials fabrication to provide an ancillary support structure that creates an essentially gas-tight enclosure. Such techniques may include the use of bulk metal housings and macroscopic sheets used as glass covers. The use of such conventional techniques for the hermetic sealing of components used in optical communications, is contrary to the miniaturization desirably afforded to such components sized for optical wavelengths.
Optical communications modules may represent the medium-scale integration of individual semiconductor die and other optoelectronic components, each comprising a different function. Hermeticity of the overall enclosure is desirable when the hermeticity of the individual components cannot be provided. Hermeticity of the overall package is required for reliable operation of the modules in adverse or non-benign environments.
Conventional methods for hermetically sealing individual die upon formation are available but such hermeticity does not extend beyond the individual die in the subassembly or module. As above, techniques for the hermetic sealing of assembled or partially assembled electronic components are also available, but such methods typically require undesirable ancillary, macroscopic support structures such as bulk housings and glass covers. It is therefore desirable to provide a method and structure for hermetically sealing a portion of an OSA or another optical communication module that includes multiple electronic components, to provide hermeticity without the use of the additional macroscopic bulk supports conventionally used in the art.